79,81Br and 133Cs Nuclei Quadrupole Interactions and Phase Transitions in Crystalline Caesium Perbromate

1990 ◽  
Vol 45 (7) ◽  
pp. 1005-1009 ◽  
Author(s):  
V. P. Tarasov ◽  
V. I. Privalov ◽  
Yu. A. Buslaev ◽  
U. Eichhoff
Keyword(s):  
Quadrupole Coupling Constant ◽  
Lattice Parameter ◽  
Coupling Constant ◽  
Linear Region ◽  
Line Shapes ◽  
Quadrupole Interactions ◽  
Quadrupole Coupling ◽  
Orientational Phase Transition ◽  
Spectral Simulations ◽  
Increasing Temperature

NMR experiments in solid caesium perbromate have recently been performed at magnetic fields of 1.88 T and 7.04 T together with spectral simulations for 79Br, 81Br and 133Cs in solid caesium perbromate. The line shapes are dominated by quadrupole effects. For bromine the quadrupole asymmetry parameter [η] is observed to be zero at all temperatures while the quadrupole coupling constant (CQ) as a function of temperature shows two approximately linear regions on either side of a non-linear region between 200 K and 260 K where an extended orientational phase transition occurs. 133Cs shows an increase of CQ and a decrease of η with increasing temperature. This behaviour may be associated with an anisotropic change of the “a” lattice parameter.

scholarly journals High Resolution and Solid State NMR Investigations of Subvalent Gallium Compounds

1986 ◽  
Vol 41 (1-2) ◽  
pp. 315-318 ◽  
Author(s):  
Hubert Schmidbaur ◽  
Theodore Zafiropoulos ◽  
Wolfgang Bublak ◽  
Paul Burkert ◽  
Frank H. Köhler
Keyword(s):  
Solid State ◽  
Nmr Spectra ◽  
Quadrupole Coupling Constant ◽  
Coupling Constant ◽  
Gallium Atom ◽  
Line Shapes ◽  
Quadrupole Coupling ◽  
Structure Determinations ◽  
Constant E ◽  
Gallium Compounds

The 71Ga NMR spectra of Ga[GaX4] melts and of solutions in benzene and other hydrocarbons show discrete sharp GaI and broad GaIII resonances. In the light of recent structure determinations, the solution GaI signals must be attributed to bis(arene)Ga+ complexes in which the gallium atom is η6-bonded to the hydrocarbons. The low line widths and strong high field shifts are attributed to an almost spherical shielding of the metal nucleus by the 4 s2 electrons. Solid state 69Ga and 71Ga NMR spectra of Ga[GaCl4] crystalline powder show only Ga1 resonances. While the 71GaI line is rather narrow, the 69GaI line has a complex fine structure. Consistent with the crystal structure of Ga[GaCl4], the Ga1 ion is calculated to have a very low quadrupole coupling constant e2q Q/h = 1.7 ± 0.1 MHz and an asymmetry parameter η = 0.44. Experimental and simulated line shapes (using literature models) are in satisfactory agreement, implying that the 69Ga signal splitting is due to second order quadrupolar effects for the central m = + 1/2 ⇋ - 1/2 transition. The analogous splitting of the 71Ga NMR line is too small to be detected.

Powder Zeeman NQR Study on 123Sb in Sb(C6H5)3

2002 ◽  
Vol 57 (6-7) ◽  
pp. 304-306
Author(s):  
O. Ege ◽  
S. Maekawa ◽  
H. Negita
Keyword(s):  
Computer Simulation ◽  
Line Shape ◽  
Asymmetry Parameter ◽  
Quadrupole Coupling Constant ◽  
Coupling Constant ◽  
Line Shapes ◽  
Quadrupole Coupling ◽  
Saddle Type ◽  
Lower Series ◽  
Good Agreement

Powder Zeeman NQR spectra of 123Sb in Sb(C6H5)3 were studied by means of a computer simulation and an experiment. The 123Sb nucleus has spin 7/2. There are two non-equivalent 123Sb atoms in the crystal of Sb(C6H5)3, so that there are two series of three transition lines (higher series: ν1h, ν2h, ν3h; lower series: ν11, ν21, v31). The powder Zeeman spectra for ν1h, based on the transition between the levels mI = ±1/2 and ±3/2, were observed at 77 K under the two conditions that i) the oscillation coil and the static magnetic coil were set coaxially and parallel, and ii) they were set perpendicular to each other. The powder line shapes for ν1h, which is the lowest line of the higher series due to 123Sb nuclei, were in good agreement with those from a computer simulation under the conditions i) and ii), showing that the asymmetry parameter of the field gradient is very small (η = 0). The line shape from i) exhibits two shoulders (saddle type), as it appeared for nuclear spin 5/2 and η = 0. The quadrupole coupling constant for 1h, calculated from the resonance frequency 47.820 MHz and the observed η, is 669.480 MHz at 77 K.

Die Temperaturabhängigkeit der Kernquadrupolkopplungskonstante von Na23 in Natriumnitrit, NaNO2

1962 ◽  
Vol 17 (9) ◽  
pp. 794-798 ◽  
Author(s):  
Alarich Weiss ◽  
D. Biedenkapp
Keyword(s):  
Asymmetry Parameter ◽  
Transition Point ◽  
Quadrupole Coupling Constant ◽  
Coupling Constant ◽  
Point Charge Model ◽  
Nuclear Quadrupole Coupling Constant ◽  
Charge Model ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole ◽  
Increasing Temperature

The nuclear quadrupole coupling constant of Na23 in sodium nitrite. NaNO2. has been investigated between 18 °C and 215 °C. Below the transition temperature (163 ± 2)°C the asymmetry parameter η= (φxx — φyy)/φzz decreases with increasing temperature and goes to zero at the transition point. Above 163 °C η is negative and | η | increases with temperature. This temperature dependence of the nuclear quadrupole coupling cannot be explained adequately by the point charge model together with the assumption of the free rotation of the NO2-group above the transition point.

scholarly journals 7Li Solid State NMR Study of a TMEDA Complex of Trimethylsilylcyclopentadienyllithium

1993 ◽  
Vol 48 (11) ◽  
pp. 1555-1557 ◽  
Author(s):  
Tanja Pietraß ◽  
Paul K. Burkert
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Solid State Nmr ◽  
Quadrupole Coupling Constant ◽  
Structural Features ◽  
Coupling Constant ◽  
X Ray ◽  
Nmr Study ◽  
Quadrupole Coupling ◽  
Increasing Temperature

7Li solid state NMR spectroscopy of Ν,Ν,N′,N′-tetramethylethylenediamine-trimethylsilylcyclopentadienyllithium yielded an unusually large quadrupole coupling constant, that decreases with increasing temperature (188-165 kHz in the temperature range 210-335 K). Structural features, known from the X-ray analysis, are compared with the NMR results.

Conformational Analysis of Chloromethylenimine and its Hydrogen-Bonded Dimers with Water from the Study of Nuclear Quadrupole Interactions

1996 ◽  
Vol 51 (5-6) ◽  
pp. 534-536 ◽  
Author(s):  
N. Sathyan ◽  
V. Santhanam ◽  
J. Sobhanadri
Keyword(s):  
Proton Affinity ◽  
Quadrupole Coupling Constant ◽  
Basis Set ◽  
Coupling Constant ◽  
Quadrupole Interactions ◽  
Nuclear Quadrupole Interactions ◽  
Nuclear Quadrupole Coupling Constant ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole ◽  
Hydrogen Bonded

Abstract A molecular conformation study on N-Chloromethylenimine and its 1:1 dimeric form with water has been carried out using the ab-initio method at 6-31 G and 6-31 G* basis set. We consider the two most stable conformers of the N-chloromethylenimine -water binary mixture involving double hydrogen bonds. In all cases the proton affinity has been calculated. Each system considered in this work has the nuclear quadrupole interactions of the nitrogen and chlorine resonant nuclei which have been calculated and compared. It is found that the nuclear quadrupole coupling constant for the nitrogen nucleus increases in the hydrogen bonded complexes and decreases for the chlorine nucleus compared to the monomeric values. The influence of proton affinity is reflected in the nuclear quadrupole coupling constant.

Nuclear Quadrupole Interactions of 27Al in Alexandrite Single Crystal

1998 ◽  
Vol 53 (6-7) ◽  
pp. 568-572 ◽  
Author(s):  
T. H. Yeom ◽  
S. H. Choh ◽  
K. S. Hong ◽  
H. Y. Yeom ◽  
Y. H. Park ◽  
...  
Keyword(s):  
Single Crystal ◽  
Asymmetry Parameter ◽  
Quadrupole Coupling Constant ◽  
Coupling Constant ◽  
Experimental Accuracy ◽  
Quadrupole Interactions ◽  
Nuclear Quadrupole Interactions ◽  
Nuclear Quadrupole Coupling Constant ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole

Abstract In an alexandrite single crystal four sets of NMR spectra for 27Al (I=5/2) were observed in the crystallographic ab, be, and ca planes. The AI (I) center has four magnetically inequivalent Al sites, whereas the AI (II) center has two. The nuclear quadrupole coupling constant and asymmetry parameter of Al(I) and AI(II) in an alexandrite crystal were determined. Within the experimental accuracy, our parameters turned out to have the same values as those of a chrysoberyl crystal.

Sign in / Sign up

Export Citation Format

Share Document